The present invention relates to grinding devices, such as grinding discs and wheels. More particularly, the present invention relates to grinding devices, such as grinding discs and wheels, wherein the grinding device is adapted to perform “dry machining” operations.
In the machining of substantially planar workpieces, such as brake rotors, power steering pump rings and rotors, valve plates, coil spring ends, and the like, it is known to pass the workpiece along the radial “face” surface of a surface grinding disc. For example, U.S. Pat. No. 6,419,564 to Herrman, et al., teaches a surface grinding machine and a surface grinding disc used therewith to machine substantially flat workpieces. In particular, Herrman '564 teaches a segmented grinding disc constructed from a circular base to which a plurality of abrasive pieces are secured in a predefined array. The abrasive pieces are arranged so as to define spaces therebetween for the purpose of allowing cooling fluids to flow over, around, in between and away from the abrasive pieces, thereby flushing swarf from the abrasive pieces and facilitating heat dissipation. According to one aspect of the present invention, it is desirable to provide a grinding device, such as, for example, a surface grinding disc or an annular grinding wheel, wherein the device includes a plurality of abrasive segments arranged in an array thereon (or therearound, as the case may be).
Herrman '564 also teaches that the abrasive pieces may include diamond or superabrasive particles, such as cubic boron nitride (“cBN”) dispersed therein for reasons which are obvious to those of ordinary skill in the art However, it is customary for machining operations being performed with such a superabrasive grinding device to require a flow of coolant to be directed thereover, as described in Herrman '564, for the purposes discussed therein. For reasons that will be obvious to one of ordinary skill in the art, such “wet machining” operations are undesirable. It is desirable, therefore, to provide a grinding device, such as, for example, a surface grinding disc or an annular grinding wheel, constructed from a plurality of abrasive segments arranged in an array thereon, wherein the abrasive segments include superabrasive particles dispersed therein, and wherein the device is adapted to operate in a “dry machining” environment, that is, for example, without the use of more than a nominal quantity of coolant or other lubricant.
The efficiency of conventional dry machining operations is limited by the rate at which workpiece material may be removed therefrom without imparting workpiece failure or damage, such as, for example, burning. This is because coolants serve an important function of dissipating heat and dry machining is—by definition—machining in a dry or near-dry environment (i.e., without the use of coolants). It is desirable therefore to provide a grinding device, such as, for example, a surface grinding disc or an annular grinding wheel, constructed from a plurality of abrasive segments arranged in an array thereon, wherein the plurality of abrasive segments are embedded in a matrix composition adapted to enhance heat dissipation.
It is desirable furthermore to provide a method of dry machining workpieces wherein the method provides a grinding device, such as, for example, a surface grinding disc or an annular grinding wheel, constructed from a plurality of abrasive segments arranged in an array thereon, wherein the plurality of abrasive segments are embedded in a matrix composition adapted to enhance heat dissipation.
It is also desirable to provide a method of dry machining workpieces with increased machining efficiency, that is, for example, by increasing workpiece material removal rates.
It is even furthermore desirable to provide a method of dry machining workpieces constructed from hard materials, which typically are difficult to dry machine using known dry machining methods and devices.